trunk between 2950 and 3548

[helecocq]

We try to establish a trunk between a 2950 and a 3548 on int GBIC

We forced switchport trnk 802.1Q and switchport mode trunk but the port comes up/down continuously

what is the probleme or good configuration

[uupsala]

are you using redundant cabling, so that the spanntree could be an issue or is it caused by a dtp problem? #show dtp interface will give you more information on this. make sure the vtp domain on both switches is the same and that the switchport is set to nonegotiate (switchport nonegotiate).

[rjackson]

Couple of years ago we had a problem with 3548XL trunks bouncing. It was a bug in the IOS. You might see how old your IOS is.

[helecocq]

hello

thanks for your reply

ios 3548 is 11.2.8 and 2950 12.0.5

is there any problem with?

[helecocq]

they is no redundant cabling, name of vtp domain vtp client are corrects

the switchport is set to negociate on 2950

i stand the client for the result of sh dtp

thanks

[Kevin Dorrell]

I found a bug on the 3548XL that looks a bit like this, but the bug report says it applies to stackable GBICs. The bug is CSCds31477, and is fixed in 12.0(5.2)XW onwards. This version also fixes a similar problem CSCds52130 on 2950.

Kevin Dorrell

Luxembourg